A dialysis apparatus as a blood purification apparatus is mainly configured to include a blood circuit with an arterial blood circuit and a venous blood circuit. The arterial blood circuit has an arterial puncture needle attached to its distal end. The venous blood circuit includes a venous puncture needle attached to its distal end. A dialyzer is interposed between the arterial blood circuit and the venous blood circuit. The dialyzer purifies blood flowing in the blood circuit. A blood pump is arranged in the arterial blood circuit. An arterial air trap chamber and a venous air trap chamber are, respectively, arranged in the arterial blood circuit and the venous blood circuit. The air trap chambers remove air bubbles. A dialysis device supplies a dialysate to the dialyzer.
In addition, a containing bag contains a physiological saline solution. The containing bag is connected, via a physiological saline solution supplying line, between the arterial puncture needle and the blood pump in the arterial blood circuit. When priming before dialysis treatment, the physiological saline solution inside the containing bag can be supplied into the blood circuit via the physiological saline solution supplying line. Thus, substitution during the dialysis treatment or returning of blood after the dialysis treatment is performed. For example, during the returning of blood, the returning of blood can be performed by supplying the physiological saline solution into the blood circuit as a substitution solution. This substitutes the blood inside the blood circuit with the substitution solution (for example, refer to Japanese Unexamined Patent Application Publication No. 2006-280775).
Incidentally, in recent years, in order to reduce the burden on health care workers, there has been an increased need to automate various procedures during blood purification treatment. For example, a blood purification apparatus has been proposed that includes a control device to alternately control a returning blood process. During returning of the blood, the returning of the blood is performed by allowing the blood pump to be in a normal rotation and substituting the substitution solution for the blood. A connection portion connects a substitution solution supplying line to a distal end of the venous blood circuit in the blood circuit. This is referred to as a venous returning blood process. The returning of blood is performed by allowing the blood pump to be in a reverse rotation and substituting the substitution solution for the blood. The connection portion connects the substitution solution supplying line to a distal end of the arterial blood circuit in the blood circuit. This is referred to as an arterial returning blood process (for example, refer to Japanese Unexamined Patent Application Publication No. 6-261938).